Generally, a camera module is an optical device formed with a plurality of lenses for photographing an object through the lenses. The lenses are embedded in a lens barrel. The lens barrel is coupled to a holder, such as a bobbin, and the holder is attached to a substrate mounted with an image sensor. At this time, the lens barrel is moved to perform a focusing process to adjust a depth of focus between the lens embedded in the lens barrel and the image sensor (i.e., focusing of the lens barrel and the image sensor).
Conventionally, after the focusing process, in order to fix the lens barrel and the holder, an epoxy is coated between the lens barrel and the holder to allow the epoxy to cure. At this time, during epoxy coating process, inattention may occur of touching the lens barrel using a coating needle to generate a problem of twisting a lens focusing.
Furthermore, the lens barrel supporting the plurality of lenses is formed at an inner surface of the bobbin of a VCM (Voice Coil Motor) for auto focusing, and each of the inner surface of the bobbin and an outer surface of the lens barrel is formed with a screw thread, by which the bobbin and the lens barrel are screw-connected for mutual coupling.
Meanwhile, in the course of assembly process coupling the bobbin and the lens barrel through screw-connection, or in the course of adjusting a position of screw-connection of the bobbin and the lens barrel for auto focusing, sticky or adhesive foreign objects such as liquid foreign objects or burrs that may exist on screw threads may be transmitted to an IRCF (Infrared Cut Filter) arranged downstream of the lens barrel. The adhesion of these foreign objects to the IRCF may cause generation of defects to the camera module such as image pollution and the like.